Hall-effect sensor chips can generate different information signals which are transformed by the electronic circuitry connected thereto to different control signals. The control signals, in turn, can, in a vehicle door lock system, bring about the different functions of the latch or bolt system and the locking system, usually via motors or other drivers or effectors which displace the elements, for example, levers of the door locks and/or energize control lamps or other signalling devices.
For example, one effector or motor can operate the bolt mechanism of a door lock for latching and unlatching that door lock, of a central locking system for the vehicle as a whole. In this arrangement and in the preferred embodiment of the invention, two Hall-sensor chips can co-act as part of the control system to signal the position or status of the lock or lock element.
When reference is made here to a latching or bolt system, we mean to describe the type of central locking system for a vehicle in which an effector can rotate the bolt of the lock into and out of engagement with the pin on the door post and can operate the usual keeper for the rotary bolt. When we refer to the lock system for this arrangement, we mean to include at least one mechanical lock cylinder which can be rotated by a mechanical key and which normally has three functional positions, namely, an intermediate starting position, a latching and unlatching position to one side of the intermediate position and in which the bolt can be operated in the manner described, and an antitheft position to the opposite side of the intermediate position and in which, upon rotation of the cylinder into this position, the door locks can be secured in an antitheft arrangement. In this position, operation of the door locks is blocked.
The locking cylinder can cooperate with the control circuitry of the vehicle door lock system which can also receive inputs or can interrogate the door locks as to current status of the positions of elements thereof or can interrogate the cylinder as to its position. To this end, the position detectors can be Hall-effect sensor chips in the manner described or the Hall-effect sensor chips can be positioned to detect the selected positions of the lock cylinder.
For example, the lock cylinders can have two fixed Hall-effect sensor chips each with a respective Hall-effect sensor and chip circuit, and a ferromagnetic element which is operatively connected or forms part of the lock cylinder and which can detect the position of the lock cylinder. The lock cylinder can have an intermediate zero position. Generally speaking the Hall-effect sensor chips or the circuitry therefor can have a lower current threshold and an upper current threshold.
Door locks of this type are described, for example, in DE 196 34 321, corresponding to U.S. application Ser. No. 08/915,897 filed 21 Aug. 1997 by Hagen FRIEDRICH, Andreas SIEKIERKA and Thorsten TORKOWSKI, and DE 296 18 688 U1, corresponding to U.S. application Ser. No. 08/950,792 filed 16 Oct. 1997 by Peter BARTEL, Johannes-Theodor MENKE and Thorsten TORKOWSKI. Reference may also be made to EP 0 694 665 A1.
The described door locks utilize Hall-effect sensor chips which can generate first information signals of a high current level I.sub.high and second information signals at a lower current amplitude I.sub.low. However, defects in Hall-effect sensor chips, in the conductive path or circuitry between a Hall-effect sensor chip and the evaluating circuitry, or in the current supply of a Hall-effect sensor chip can arise and can interfere with the operation of such systems.